The low power shutoff at 11.2v is meant as a backup, as not all cars will be happy to start at 11.2v. Yours may not have a problem, now, it develop a problem as your battery gets older, or it may work perfectly for you. Personally, I don't see an advantage of never going hardoff because I use hibernate and it doesn't matter if it has power or not, and any possible advantages are very small if I get in to a car that has a dead battery.
There are two pins, a 12v and a ground if memory serves. Depending on what your amp needs to turn on. Check what it says for j6 in the manual.
I just have my system start when I start the car. It only takes a few seconds to get music. If for some reason I want music right now, I switch to the radio or cd player.